SIALADENOMA PAPILLIFERUM - AN IMMUNOHISTOCHEMICAL STUDY OF 5 CASES

Sialadenoma papilliferum (SP) is a rare, benign, salivary gland tumor which most commonly arises in the palate. It has a typical biphasic gr oss and microscopic appearance which distinguishes this tumor from oth er papillary-like tumors of the oral cavity. This study reports the cl inico-pathologic features of 5 new cases and analyzes the morphologic and immunophenotypic features of their cell components, Adluminal epit helial cells of duct-like structures appeared immunoreactive to cytoke ratin 19 and to S-100 protein antibodies; two subsets of basally-locat ed cells were identified by means of immunohistochemistry. One cell su bset expressed cytokeratin 14, S-100 protein, GFAP, vimentin and smoot h muscle actin immunoreactivity: this antigenic profile is consistent with myoepithelial differentiation. The second subset of basal cells e xpressed cytokeratins 13 and 14 reactivity but it was negative to all other antibodies. Anti-CD 1a and anti-S-100 protein antibodies reveale d distinct cells with dendritic processes which resembled Langerhans c ells, The extralobular location of SP, the continuity between neoplast ic duct-like structures and the surface epithelium along with the pres ence, within the excretory ducts adjacent to the tumour, of lesions wh ich possibly precede the development of SP give further strength to th e hypothesis of an origin from the excretory ducts of this tumor. Lang erhans cells seem to be present in sialadenoma papilliferum but their role in this tumor is still unclear.